feat: implement Supabase database schema and core authentication flow with registration and login pages

supabase/schema.sql

@@ -121,3 +121,62 @@ create policy "Users can delete their own chat messages." on public.chat_message
       and chat_sessions.user_id = auth.uid()
     )
   );
+
+
+-- 5. Create profiles table
+create table public.profiles (
+  id uuid references auth.users(id) on delete cascade primary key,
+  first_name text,
+  last_name text,
+  avatar_url text,
+  updated_at timestamp with time zone default timezone('utc'::text, now()) not null
+);
+
+alter table public.profiles enable row level security;
+
+create policy "Users can view their own profile." on public.profiles
+  for select using (auth.uid() = id);
+create policy "Users can insert their own profile." on public.profiles
+  for insert with check (auth.uid() = id);
+create policy "Users can update their own profile." on public.profiles
+  for update using (auth.uid() = id);
+
+-- Function to handle new user signup
+create or replace function public.handle_new_user()
+returns trigger as $$$
+begin
+  insert into public.profiles (id, first_name, last_name, avatar_url)
+  values (new.id, '', '', '');
+  return new;
+end;
+$$$ language plpgsql security definer;
+
+-- Drop trigger if exists to avoid errors on multiple runs
+drop trigger if exists on_auth_user_created on auth.users;
+
+-- Trigger to automatically create profile on signup
+create trigger on_auth_user_created
+  after insert on auth.users
+  for each row execute procedure public.handle_new_user();
+
+-- Setup storage bucket for avatars
+insert into storage.buckets (id, name, public) 
+values ('avatars', 'avatars', true)
+on conflict (id) do nothing;
+
+create policy "Avatar images are publicly accessible."
+  on storage.objects for select
+  using ( bucket_id = 'avatars' );
+
+create policy "Users can upload an avatar."
+  on storage.objects for insert
+  with check ( bucket_id = 'avatars' AND auth.uid()::text = (storage.foldername(name))[1] );
+
+create policy "Users can update their own avatar."
+  on storage.objects for update
+  using ( bucket_id = 'avatars' AND auth.uid()::text = (storage.foldername(name))[1] );
+
+create policy "Users can delete their own avatar."
+  on storage.objects for delete
+  using ( bucket_id = 'avatars' AND auth.uid()::text = (storage.foldername(name))[1] );
+